The Glenstone Program: Your Lawn Could Be This Healthy, Too

Instantly transitioned from a strict synthetic chemical program to all-organic protocols in July of 2010, the lawn at Glenstone in Potomac, Md., is shimmering green and predominantly weed-free this fall.

POTOMAC, MD. — The living, evolving science project at the modern art museum known as Glenstone continues to show dramatic results from its organic landscape transformation started nearly two and a half years ago.

“There’s almost too much growth from the composted plots,” said Dr. Thomas Turner during his recent monthly evaluation of the carefully calibrated test plots that the University of Maryland Turfgrass Research Department is maintaining on the Glenstone campus.

When SafeLawns was first called to the 160-acre estate in July of 2010 we were asked to create a set of protocols to instantly transition the property away from synthetic chemical management. In turn, SafeLawns asked the museum’s benefactors to fund a research project with the turfgrass department at the state university so those same protocols could be scientifically monitored and, ideally, have the results formally published.

These are the 10-by-10-foot research plots at Glenstone. The darkest green plot near the center of this photo was top-dressed with a biosolids compost four weeks earlier.

“What was interesting was the initial reaction of the grounds people here who said, ‘We can’t do that, it will be a disaster,’” said Glenstone co-founder Mitchell Rales during an interview aired this summer on Growing a Greener World with Joe Lamp’l. “What I learned in my business career over the course of time is that leadership needs to come from the top. If you don’t drive (change) from the top right away, it can’t happen.”

In addition to maintaining a lush, green appearance, the landscape at Glenstone has also helped the facility’s bottom line financially. The museum staff estimated a 15 percent savings in 2011 by shifting to organics from synthetic chemicals, primarily due to the elimination of an integrated pest management program that called for blanket insect and weed spraying. Though figures have not yet been calculated for 2012, we expect similar results.

Here, briefly, is a rundown of the Glenstone program:

SOIL TESTING — Anyone attempting to assess what a landscape truly needs in terms of fertility needs to test the soil first. Glenstone didn’t cut any corners by ordering tests of both the chemistry — pH, cation exchange, nutrient content and organic matter — along with the biology. This latter test, known as a bioassay, evaluates levels of bacteria, protozoa, fungi and other microscopic life. Certain biological thresholds are necessary to obtain success in an organic program.

ORGANIC MATTER — The initial tests at Glenstone showed the predominantly clay soils contained less than 1 percent organic matter. We know optimum to be a minimum of 5 percent, so we immediately ordered a 400-cubic-yard load of compost in bulk — enough to blanket the 16 acres of grass with slightly less than a quarter inch of compost. This is enough to make a difference, but not so much that it would smother the crowns of the grass plants. Within three days, the grass was several shades darker green. Had we not “top-dressed” with compost, the transformation to organics would have taken longer and likely not been as successful. We have subsequently top-dressed the soil on three additional occasions and the soil now contains more than 4 percent organic matter overall.

MOWING & AERATING — When we arrived at Glenstone the crew was bagging the clippings across all 16 acres and also keeping the blade at about 2 inches in height. Right away we told them to leave the clippings on the lawn — which meant the crew could save money and therefore time by mowing three- to four-times as fast. The clippings quickly biodegrade and essentially become free organic fertilizer for the lawn.

We also told the crew to raise the height of the mower’s blade to 3.5 inches at a minimum. With the horrific (for landscapes) heat of the Potomac region in the summer, the taller the grass the better it will withstand the summer beating and also outcompete weeds.

Due to the compaction of the clay soils, we also ordered an aeration of the entire campus in the fall just prior to a second coating of compost. The aeration reduces compaction by allowing air, compost and water to get down into the root system more quickly. Organic lawns will eventually self-aerate due to the presence of worms and microorganisms, but chemically treated clay soils will create a hard-pan layer that can take several years to overcome.

FERTILITY — We supplemented the nutrients from the compost with an organic fertilizer derived from alfalfa. It’s a slow-release granular product that looks and smells like animal feed — because that’s essentially what it is. We also applied compost tea at the rate of 50 gallons per acre simultaneously with the fertilizer; our experience has shown that the microorganisms in the compost tea break down the organic fertilizer more quickly and therefore green up the lawn more rapidly.

We continued to apply compost tea bi-monthly throughout the growing season. Though the scientific community is still divided on the efficacy of compost tea for disease suppression, the Glenstone campus has gone without any significant disease infestations in the past 27 months.

Clover, which fixes nitrogen from the atmosphere and provides food for insects and animals, has been accepted as part of the lawn at Glenstone.

SOIL AMENDMENTS — The pH of the soils at Glenstone was within the range of 6.2-7.0 that we ideally look for when growing grass for lawns, but the calcium-to-magnesium ratio was out of kilter with too much magnesium. To minimize weed pressure the balance of calcium should be seven times greater than magnesium, so we recommended the application of gypsum, especially in the highly compacted areas. Adding high-calcium limestone would have given us the needed calcium, but also would have raised the pH too high into the alkaline range.

Our tests in the spring of 2012 indicated that we’re still somewhat low on the Ca-Mg ratio, so we’ll apply another blanket application of gypsum this fall across the entire campus.

WEED CONTROL — In 2010, we really didn’t see any dicot, aka broadleafed, weeds on the lawn. The campus was fairly free of things like clover, plantain and dandelions due to a synthetic chemical weed-killing program. That was true for those first few months, even after the first phase of the organic transition.

Part of the control program was to set the expectation bar in the appropriate place. In fact, we told Glenstone not to hire us if they couldn’t stand a certain percentage of clover, which has been an integral component of any natural lawn systems since kings hired peasants to scythe down fields. The arrival of clover is Mother Nature’s natural response whenever synthetic chemical nitrogen is removed from a landscape in the temperate region of North America. Other legumes will fill into other lawns in warm-season regions of the nation.

As the second year progressed at Glenstone, the clover arrived as predicted, but not in percentages that the owners found troublesome. We also began experimenting with spot spraying of Fiesta, the world’s first natural “selective” herbicide that allows grass to grow, but kills the dicot weeds including clover and dandelions. The bottom line: it works well on many weeds when you apply it properly. For some weeds it will require two applications and, compared to the toxic chemicals like 2,4-D and mecroprop, it’s fairly expensive for blanket applications.

We utilized bagging attachments on the mowers in mid September when small patches of crabgrass were visible on the Glenstone lawn.

Our weed approach is far more cultural than product oriented. We mow higher from spring to fall so that the surface of the soil is shaded by grass and weed seeds are less likely to germinate. We overseed with grass seed whenever bare spots arise and then do a blanket application of seed in the fall (see below). We pluck weeds by hand from time to time, and then will spend a couple of days with a crew of three to four workers in the fall to hand pull the majority of any weeds that have sprouted. The process is tedious across 16 acres of turf, and they’re not anyone’s favorite days of the year, but the cost and time is more than balanced out by the savings to be found in the rest of the program.

As stated earlier, we no longer bag the grass at Glenstone — most of the time. This fall, however, we did put the bags on the mower in sections of the lawn where small patches of crabgrass had sprouted. We didn’t want those seedheads dropping off and hitting the ground, so the mower bag was the most efficient way to collect them when we ran out of time for hand pulling.

If bare areas develop after weeding, or due to dogs or equipment etc., it’s best to immediately cover the area with compost and overseed — keeping the area constantly moist until the grass germinates.

Broadleafed weeds, in general, have not been a significant issue at Glenstone. If anything has been a problem in some folks minds, it would be the grassy weeds. In summer, Bermuda grass outcompetes the turf type tall fescue that is the predominant species at Glenstone. If some areas get too wet, then sometimes nutsedge will move in. All these are green, and they’re grass-like, but the grow in different color tones and at different rates. If a perfect blemish-free carpet is the ultimate goal, then grassy weeds can be seen as a problem.

OVERSEEDING — Rather than rush out for synthetic chemical weed killers, or to eliminate certain undesirable grasses, Glenstone has invested money instead on grass seed. Aggressively overseeding thin, bare areas is perhaps the primary weed-control tool at Glenstone aside from ensuring healthy soil and grass mown at the proper height. Leaving any areas bare for even a day is a recipe for weed trouble.

Whether you’re managing a home lawn, or a commercial landscape, make sure a seeding program becomes part of your annual plan. It’s a simple process — provided special attention is paid to watering and keeping the seed moist until it germinates. It’s easy to let this job slide for a day or three and, when it’s hot, the seed may not come up.

THE FUTURE — Glenstone has stated its ongoing commitment to refinement of the organic program. As the facility plans for a major expansion in years ahead it intends to get the soil healthy right from the start, which is good advice for anyone. We continue to experiment with different kinds of organic fertilizers and weed killers as they come onto the market and, when something really catches our eyes, we’ll share the information broadly.

We know the common-sense, practical program works; the proof is in the green grass on the magnificent campus where a seamless integration of art, architecture and landscaping have come together. Yet we’re excited, too, that the University of Maryland turfgrass team recently finished its second-annual organic applications and that the scientific evaluation process is building a body of valuable information. If all goes well a peer-reviewed paper will be generated in the coming years.

It’s all part of bringing what we call The Glenstone Model for the New American Landscape to a broader audience.

Researchers Dr. Mark Carroll, back left, and Dr. Thomas Turner, back center, are leading the trials at Glenstone.

About The Author

An international leader of the green movement, Mr. Tukey is a journalist, author, filmmaker, TV host, activist and award-winning public speaker, who is widely recognized as North America's leading advocate for landscape sustainability and toxic pesticide reduction strategies.